U.S. patent number 10,027,004 [Application Number 15/222,836] was granted by the patent office on 2018-07-17 for apparatus including a dielectric material disposed in a waveguide, wherein the dielectric permittivity is lower in a mode combiner portion than in a mode transition portion.
This patent grant is currently assigned to THE BOEING COMPANY. The grantee listed for this patent is THE BOEING COMPANY. Invention is credited to Ted R. Dabrowski, Larry L. Savage, Corey M. Thacker.
United States Patent |
10,027,004 |
Savage , et al. |
July 17, 2018 |
Apparatus including a dielectric material disposed in a waveguide,
wherein the dielectric permittivity is lower in a mode combiner
portion than in a mode transition portion
Abstract
An apparatus includes a waveguide. The waveguide includes a
waveguide wall having a shape associated with a dominant
propagation mode. The waveguide includes a first dielectric
material having a cross-sectional area that varies along a length
of a portion of the waveguide.
Inventors: |
Savage; Larry L. (Huntsville,
AL), Dabrowski; Ted R. (Madison, AL), Thacker; Corey
M. (Madison, AL) |
Applicant: |
Name |
City |
State |
Country |
Type |
THE BOEING COMPANY |
Chicago |
IL |
US |
|
|
Assignee: |
THE BOEING COMPANY (Chicago,
IL)
|
Family
ID: |
58772758 |
Appl.
No.: |
15/222,836 |
Filed: |
July 28, 2016 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20180034126 A1 |
Feb 1, 2018 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01P
5/024 (20130101); H01P 1/16 (20130101); H01P
5/087 (20130101); H01P 11/001 (20130101); H01P
3/16 (20130101); H01P 3/122 (20130101); H01Q
13/025 (20130101) |
Current International
Class: |
H01P
1/16 (20060101); H01P 3/16 (20060101); H01P
3/12 (20060101); H01P 11/00 (20060101) |
Field of
Search: |
;333/21R,34 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Balanis, "Advanced Engineering Electromagnetics", Wiley, New
Jersey, United States, 2012, pp. 483 through 500. cited by
applicant .
Nagelberg, et al., "Mode Conversion in Circular Waveguides", Bell
System Technical Journal, vol. 44, Issue 7, Sep. 1965, pp. 1321
through 1338. cited by applicant .
Extended European Search Report for Application No. 17172765.4,
dated Dec. 11, 2017, 9 pgs. cited by applicant .
Leong, M. S., et al., "Modal analysis of dielectric-sleeve-loaded
circular waveguide for dual-mode radiator applications," IEE
Proceedings, vol. 134, No. 4, Aug. 1987, 369-374. cited by
applicant.
|
Primary Examiner: Lee; Benny
Attorney, Agent or Firm: Toler Law Group, PC
Claims
What is claimed is:
1. An apparatus comprising: a waveguide including: a feed portion;
a mode combiner portion; a mode transition portion located between
the feed portion and the mode combiner portion; a waveguide wall
having a shape associated with a dominant propagation mode; and a
first dielectric material having a cross-sectional area that varies
along a length of a portion of the waveguide, wherein an interior
region of the mode combiner portion has a lower permittivity than
an interior region of the mode transition portion.
2. The apparatus of claim 1, wherein the waveguide wall has a
circular cross-section and the dominant propagation mode comprises
a transverse electric 11 (TE11) mode.
3. The apparatus of claim 2, wherein the first dielectric material
has a tapered shape.
4. The apparatus of claim 3, wherein the tapered shape comprises a
conical shape, an elliptic shape, or a logarithmic shape.
5. The apparatus of claim 2, wherein the first dielectric material
has a dimension that varies linearly along the length of the
portion of the waveguide.
6. The apparatus of claim 1, wherein a cross-sectional area of an
interior region along the feed portion, a cross-sectional area of
the interior region along the mode combiner portion, and a
cross-sectional area of the interior region along the mode
transition portion are substantially equal.
7. The apparatus of claim 1, wherein the waveguide further
comprises an index matcher comprising a second dielectric material,
the index matcher disposed proximate to a second end of the
waveguide.
8. The apparatus of claim 7, wherein the portion of the waveguide
includes the mode transition portion, and wherein the mode combiner
portion is disposed between the mode transition portion and the
second end.
9. The apparatus of claim 8, wherein the feed portion is disposed
between the mode transition portion and a first end of the
waveguide, and wherein an interior region of the feed portion has a
lower permittivity than the interior region of the mode transition
portion.
10. The apparatus of claim 9, wherein a cross-sectional area of an
interior region of the waveguide is substantially constant along a
length of the mode transition portion.
11. The apparatus of claim 10, wherein the cross-sectional area of
the interior region of the waveguide is substantially constant
along the feed portion, and wherein the cross-sectional area of the
interior region along the length of the mode transition portion and
the cross-sectional area of the interior region along the feed
portion are substantially equal.
12. A waveguide comprising: a feed portion; a mode combiner
portion; a mode transition portion including a dielectric material,
the mode transition portion located between the feed portion and
the mode combiner portion, wherein an interior region of the mode
combiner portion has a lower permittivity than an interior region
of the mode transition portion; and an index matcher comprising the
dielectric material, wherein the mode combiner portion is located
between the index matcher and the mode transition portion.
13. The waveguide of claim 12, wherein the dielectric material has
a cross-sectional area that varies along a length of the mode
transition portion.
14. The waveguide of claim 13, wherein the dielectric material has
a tapered shape.
15. The waveguide of claim 12, wherein a cross-sectional area of
the interior region along the feed portion, a cross-sectional area
of an interior region along the mode combiner portion, and a
cross-sectional area of the interior region along the mode
transition portion are substantially equal.
16. A method comprising: receiving a signal at a waveguide, the
waveguide comprising a waveguide wall and a dielectric material
having a cross-sectional area that varies along a length of a
portion of the waveguide, wherein a shape of the waveguide wall is
associated with a dominant propagation mode; and converting a
portion of the signal from the dominant propagation mode to a
second propagation mode by propagating the signal through the
portion of the waveguide that includes the dielectric material,
wherein the portion of the waveguide comprises a mode transition
portion between a feed portion and a mode combiner portion, and
wherein an interior region of the mode combiner portion has a lower
permittivity than an interior region of the mode transition
portion.
17. The method of claim 16, wherein the waveguide wall has a
circular cross-section and the dominant propagation mode comprises
a transverse electric 11 (TE11) mode.
18. The method of claim 16, wherein the second propagation mode
comprises a transverse magnetic 11 (TM11) mode.
19. The method of claim 16, further comprising propagating the
signal through the mode combiner portion of the waveguide.
20. The method of claim 16, wherein the mode combiner portion has a
length that causes energy propagating in the dominant propagation
mode and energy propagating in the second propagation mode to have
a target phase difference at an end of the waveguide wall.
Description
FIELD OF THE DISCLOSURE
The present disclosure relates to waveguides.
BACKGROUND
Microwave antennas may emit energy having a radiation pattern that
includes a main lobe and side lobes. The side lobe energy may be
undesirable. For example, the side lobe energy may draw energy from
the main lobe and may make detection of an emitter easier. Side
lobe energy may be reduced by reducing longitudinal edge currents
at the mouth of an aperture antenna or a waveguide. The
longitudinal edge currents may be reduced by propagating energy in
a mixed propagation mode including a dominant propagation mode and
a higher order propagation mode to cancel longitudinal current. The
mixed propagation mode may result from converting energy
propagating in the dominant propagation mode to energy propagating
in the higher order propagation mode. A dimension (e.g., a
cross-sectional area of an interior region) of the waveguide may be
varied along its length in order to present a boundary value
perturbation that causes energy propagating in the dominant
propagation mode to convert to energy propagating in the higher
order propagation mode. For example, the wall of the waveguide may
include a flare, an iris, a groove, or a step to convert energy to
the higher order propagation mode. However, varying the
cross-sectional area of the waveguide wall may be undesirable. For
example, many systems include waveguides that have a substantially
constant cross-sectional area and it would be costly to replace the
waveguides in these systems.
SUMMARY
In a particular implementation, an apparatus includes a waveguide.
The waveguide includes a waveguide wall having a shape associated
with a dominant propagation mode. The waveguide includes a first
dielectric material having a cross-sectional area that varies along
a length of at least a portion of the waveguide.
In another particular implementation, a waveguide includes a feed
portion, a mode combiner portion, a mode transition portion, and an
index matcher. The mode transition portion includes a dielectric
material and is located between the feed portion and the mode
combiner portion. The index matcher includes a dielectric material.
The mode combiner portion is located between the index matcher and
the mode transition portion.
In another particular implementation, a method includes receiving a
signal at a waveguide. The waveguide includes a waveguide wall and
a dielectric material having a cross-sectional area that varies
along a length of a portion of the waveguide. A shape of the
waveguide wall is associated with a dominant propagation mode. The
method further includes converting a portion of the signal from the
dominant propagation mode to a second propagation mode by
propagating the signal through the portion of the waveguide that
includes the dielectric material.
The features, functions, and advantages described herein can be
achieved independently in various embodiments or may be combined in
yet other embodiments, further details of which are disclosed with
reference to the following description and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A illustrates a perspective view of a waveguide that includes
a mode transition portion;
FIG. 1B illustrates a cross-section view of a feed portion of the
waveguide of FIG. 1A;
FIG. 1C illustrates a cross-section view of a mode transition
portion of the waveguide of FIG. 1A;
FIG. 1D illustrates a cross-section view of a mode combiner portion
of the waveguide of FIG. 1A;
FIG. 1E illustrates a side cross-section view of the waveguide of
FIG. 1A;
FIG. 2 illustrates a perspective view of a dielectric material (of
a mode transition portion of the waveguide) that has a conical
taper;
FIG. 3 illustrates a side view of a dielectric material (of a mode
transition portion of the waveguide) that has an elliptic
taper;
FIG. 4 illustrates a side view of a dielectric material (of a mode
transition portion of the waveguide) that has a logarithmic
taper;
FIG. 5 illustrates an example of surface currents of a circular
waveguide that does not include the mode transition portion of FIG.
1A;
FIG. 6 illustrates an example of surface currents of a circular
waveguide that includes the mode transition portion of FIG. 1A;
FIG. 7 is a flow chart that illustrates a particular example of a
method of propagating a signal through a waveguide including
dielectric material having a cross-sectional area that varies along
a length of a portion of the waveguide;
FIG. 8 is a flow chart illustrative of a life cycle of an aircraft
that includes a waveguide including a mode transition portion;
and
FIG. 9 is a block diagram of an illustrative embodiment of an
aircraft that includes a waveguide including a mode transition
portion.
DETAILED DESCRIPTION
Particular embodiments of the present disclosure are described
below with reference to the drawings. In the description, common
features are designated by common reference numbers throughout the
drawings.
The figures and the following description illustrate specific
exemplary embodiments. It will be appreciated that those skilled in
the art will be able to devise various arrangements that, although
not explicitly described or shown herein, embody the principles
described herein and are included within the scope of the claims
that follow this description. Furthermore, any examples described
herein are intended to aid in understanding the principles of the
disclosure and are to be construed as being without limitation. As
a result, this disclosure is not limited to the specific
embodiments or examples described below, but by the claims and
their equivalents.
FIG. 1A illustrates a perspective view of a waveguide 100 including
a mode transition portion (e.g., portion 106). The waveguide 100
includes a mode combiner portion 108 between the mode transition
portion and an index matcher 112. FIG. 1B illustrates a
cross-sectional view of the waveguide 100 of FIG. 1A along line B
of FIG. 1A, FIG. 1C illustrates a cross-sectional view of the
waveguide 100 of FIG. 1A along line C of FIG. 1A, and FIG. 1D
illustrates a cross-sectional view of the waveguide 100 of FIG. 1A
along line D of FIG. 1A. FIG. 1E illustrates a cross-sectional view
of the waveguide 100 of FIG. 1A along lines A-A of FIG. 1A. As
shown in FIG. 1E, the waveguide 100 includes a dielectric material
110 having a dimension (e.g., a radius, diameter, or length of a
cross-section) that varies along a length of a portion 106 (e.g., a
mode transition portion) of the waveguide 100. The waveguide 100
includes a waveguide wall 102 having a first end 114 and a second
end 116. The waveguide wall 102 may have a cross-sectional shape
(e.g., a geometry) associated with a dominant propagation mode. For
example, the waveguide wall 102 may be circular (e.g., the
waveguide 100 may be a circular waveguide), and the dominant
propagation mode may correspond to a transverse electric 11 (TE11)
mode. Alternatively, the waveguide wall 102 may be square or
rectangular (e.g., the waveguide 100 may be a square waveguide or a
rectangular waveguide), and the dominant propagation mode may
correspond to a TE10 mode.
The waveguide 100 includes a feed portion 104 that supports
propagation of energy in the dominant propagation mode. To
illustrate using a circular waveguide, the feed portion 104
receives a signal 103 and the signal 103 propagates toward the
portion 106 entirely or predominantly in the dominant propagation
mode (e.g., TE11).
The feed portion 104 of the waveguide 100, as shown in FIG. 1A may
include an interior region 195, as shown in FIG. 1B defined or
bounded by an inner surface 197, as shown in FIGS. 1B, 1C and 1D of
the waveguide wall 102 along the feed portion 104 of the waveguide
100. In the illustrated implementation, as shown in FIG. 1B, (e.g.,
for a circular waveguide), the interior region 195 has a
cross-sectional area (A) corresponding to A=.pi.R^2 (Equation 1)
along a length of the feed portion 104, where R corresponds to the
radius R of a cross-section of the interior region 195. In other
implementations (e.g., for a square or a rectangular waveguide),
the interior region 195 of the waveguide 100 has a cross-sectional
shape other than a circle. In these examples, the interior region
195 of the feed portion 104 defined by the waveguide wall 102 has a
cross-sectional area that is defined using a different relation
than the relation of Equation 1. For example, as described above,
the waveguide wall 102 may be square or rectangular (e.g., the
inner surface 197 of the waveguide wall 102 may define a square or
a rectangle). To illustrate, the inner surface 197 along the feed
portion 104 may define a square, and the interior region 195 may
have a cross-sectional area corresponding to a length (of a
cross-sectional shape defined by the inner surface 197 along the
feed portion 104) squared. As another example, the inner surface
197 along the feed portion 104 may define a rectangle, and the
interior region 195 may have a cross-sectional area corresponding
to a length of a cross-sectional shape defined by the inner surface
197 along the feed portion 104 multiplied by a width of the
cross-sectional shape.
The interior region 195 of the feed portion 104 may have a lower
permittivity than the interior region of the portion 106. For
example, the interior region 195 of the feed portion 104 may be
filled with air, which has a lower permittivity than the dielectric
material 110 of the portion 106 as described in more detail
below.
As shown in FIG. 1E, the signal 103 propagates from the feed
portion 104 to the portion 106. The signal 103 approaching or
entering the portion 106 from the feed portion 104 is propagating
predominantly or entirely in the dominant propagation mode. The
dielectric material 110 of the portion 106 serves to convert some
portions of the signal 103 propagating in the dominant propagation
mode at entry into the portion 106 (i.e., at a first end 187) to
energy propagating in the second mode at a second end 188 of the
portion 106.
The portion 106 of the waveguide 100 may include an interior region
196 and the waveguide wall 102 along the portion 106 of the
waveguide 100. As shown in FIG. 1C, the interior region 196 is
defined or bounded by the inner surface 197 of the waveguide wall
102. In some implementations (e.g., for a circular waveguide), the
interior region 196 has a cross-sectional area (A) corresponding to
A=.pi.R^2 (Equation 2) along a length of the portion 106, where R
corresponds to the radius R of a cross-section of the interior
region 196. In other implementations (e.g., for a square or a
rectangular waveguide), the interior region 196 of the waveguide
100 has a cross-sectional shape other than a circle. In these
examples, the interior region 196 of the portion 106 has a
cross-sectional area that is defined using a different relation
than the relation of Equation 2. For example, as described above,
the waveguide wall 102 may be square or rectangular (e.g., the
inner surface 197 of the waveguide wall 102 may define a square or
a rectangle). To illustrate, the inner surface 197 along the
portion 106 may define a square, and the interior region 196 may
have a cross-sectional area corresponding to a length (of a
cross-sectional shape defined by the inner surface 197 along the
portion 106) squared. As another example, the inner surface 197
along the portion 106 may define a rectangle, and the interior
region 196 may have a cross-sectional area corresponding to a
length of a cross-sectional shape defined by the inner surface 197
along the portion 106 times a width of the cross-sectional
shape.
In an illustrative implementation, the interior region 196 of the
portion 106 has a substantially constant cross-sectional area along
the length and has the same cross-sectional area as the interior
region 195 of the feed portion 104. In this implementation, the
portion 106 does not include any waveguide wall perturbations.
In an illustrative implementation, as shown in FIG. 1E, the
dielectric material 110 causes the signal 103 to behave as though
the cross-sectional area of the interior region 196 is increasing
along the length of the portion 106 without actually varying the
cross-sectional area of the interior region 196. The dielectric
material 110 may cause the signal 103 to behave as though the
cross-sectional area of the interior region 196 is larger than the
cross-sectional area of the interior region 195 of FIG. 1B, because
the interior region 196 of FIG. 1C, of the portion 106 has a higher
permittivity than the interior region 195 of the feed portion 104
(e.g., based on the dielectric material 110 having a larger
dielectric constant than the material of the interior region 195 of
the feed portion 104). For example, the interior region 195 of the
feed portion may be filled with air (e.g., having a dielectric
constant of one (1)) and the dielectric material 110 may have a
dielectric constant that is larger than one (1). In some examples,
the dielectric material 110 may be formed of a polymer.
In some implementations of a circular waveguide, the dielectric
material 110 is configured to emulate a waveguide wall having an
inner surface that defines a cross-sectional shape (at the second
end 188 of the portion 106) having a radius that is approximately
twice the radius R of the feed portion 104. In these examples, the
dielectric material 110 may have a dielectric constant that is
approximately four times the dielectric constant of the material or
fill of the interior region 195 of the feed portion 104. For
example, the interior region 195 of the feed portion 104 may be
filled with air (e.g., having a dielectric constant of one (1)) and
the dielectric material 110 may be formed of a dielectric material
having a dielectric constant of about four (4).
Although the dielectric material 110 is illustrated as having a
circular cross-section, in other implementations the dielectric
material 110 may have a cross-sectional shape other than a circle.
For example, as described above, the waveguide 100 may be a square
or rectangular waveguide. In these examples, the dielectric
material 110 has a square or rectangular cross-sectional shape. In
some examples of a square waveguide 100, the dielectric material
110 has a substantially pyramidal shape when the dielectric
material 110 is linearly tapered. In these examples, the dielectric
material 110 may be configured to emulate a waveguide wall having
an inner surface that defines a cross-sectional shape (e.g., a
square or rectangular cross-sectional shape) at the second end 188
of the portion 106 having a dimension other than a radius (e.g.,
having a length or a width) that is approximately or at least twice
a value of the corresponding dimension of the cross-sectional shape
of the interior region 195 of the feed portion 104.
In this manner, the portion 106 (including the dielectric material
110) may emulate a perturbation in the waveguide wall 102 and
serves to convert energy from the dominant (e.g., a TE11)
propagation mode to the secondary (e.g., a TM11) propagation mode
without using perturbations in the waveguide wall 102. Thus, the
portion 106 may convert propagation modes while having the same (or
substantially the same) cross-sectional area as the feed portion
104, thereby enabling constant cross-sectional area waveguides to
be retrofitted to perform mode conversion by adding the dielectric
material 110 to the waveguides.
In some examples, the cross-sectional area of the dielectric
material 110 increases along the length of the portion 106 in the
direction from the first end 114 to the second end 116 (e.g., in
the direction d in FIG. 1E). In some examples, the dielectric
material 110 has a dimension (e.g., a radius) that varies linearly
along the length of the portion 106. For example, FIG. 2
illustrates an example of the dielectric material 110 of FIG. 1E
having a cross-sectional area that increases along the length of
the portion 106 in the direction d in FIG. 1E, and the dielectric
material 110 has a conical shape (e.g., a conical geometry). In
this example, the cross-sectional area at E of the dielectric
material 110 corresponds to the area of the circle E and the
cross-sectional area at F of the dielectric material 110
corresponds to the area of the circle F. In this example, the cross
sectional area at F is larger than the cross-sectional area at E,
and the cross-sectional area of the dielectric material 110
increases along the length in the direction d.
Although the dielectric material 110 is illustrated as having a
conical shape in FIG. 2, in other examples the dielectric material
110 may have a different tapered shape. For example, the dielectric
material 110 may have an elliptic or logarithmic taper. For
example, FIG. 3 illustrates the dielectric material 110 of FIG. 1E
having an elliptic taper along the length in the direction d, and
FIG. 4 illustrates the dielectric material 110 of FIG. 1E having a
logarithmic taper along the length in the direction d.
With reference again to FIG. 1E, the waveguide 100 includes the
mode combiner portion 108 between the portion 106 and the second
end 116. The mode combiner portion 108 includes an interior region
198 (see FIG. 1D) defined or bounded by the inner surface 197 in
FIG. 1D of the waveguide wall 102 along a length of the mode
combiner portion 108 of the waveguide 100. In some implementations
(e.g., for a circular waveguide), the interior region 198 has a
cross-sectional area (A) corresponding to A=.pi.R^2 (Equation 3)
along the length of the mode combiner portion 108, where R
corresponds to the radius R of a cross-section of the interior
region 198. In other implementations (e.g., for a square or a
rectangular waveguide), the interior region 198 of the waveguide
100 has a cross-sectional shape other than a circle. In these
examples, the interior region 198 of the mode combiner portion 108
has a cross-sectional area that is defined using a different
relation than the relation of Equation 3. For example, as described
above, the waveguide wall 102 may be square or rectangular (e.g.,
the inner surface 197 of the waveguide wall 102 may define a square
or a rectangle). To illustrate, the inner surface 197 along the
mode combiner portion 108 may define a square, and the interior
region 198 may have a cross-sectional area corresponding to a
length (of a cross-sectional shape defined by the inner surface 197
along the mode combiner portion 108) squared. As another example,
the inner surface 197 along the mode combiner portion 108 may
define a rectangle, and the interior region 198 may have a
cross-sectional area corresponding to a length of a cross-sectional
shape defined by the inner surface 197 along the mode combiner
portion 108 times a width of the cross-sectional shape.
The interior region 198 of the mode combiner portion 108 has a
lower permittivity than an interior region of the portion 106. In
some examples, the interior region of the mode combiner portion 108
is filled with air, which has a lower permittivity than the
dielectric material 110.
A cross-sectional area of the interior region 198 along the length
of the mode combiner portion 108 may be substantially the same as a
cross-sectional area of the interior region 196 in FIG. 1C along
the length of the portion 106. The mode combiner portion 108 may be
associated with the dominant (e.g., a TE11) propagation mode such
that energy in the secondary (e.g., a TM11) propagation mode
extinguishes as it propagates along the mode combiner portion 108
in the direction d. Additionally, the mode combiner portion 108 has
a length that causes energy propagating in the dominant propagation
mode and energy propagating in the second propagation mode to have
a particular phase difference at the second end 116. The particular
phase difference may result in cancellation of longitudinal edge
current. Cancellation of the longitudinal edge current may reduce a
side lobe energy of a radiation pattern of a signal transmitted at
the second end 116.
The waveguide 100 includes the index matcher 112, as shown in FIGS.
1A and 1E. The index matcher 112 is located proximate to the second
end 116 and may be formed of dielectric material. The index matcher
112 may support propagation of the signal 103 in the second
propagation mode. As described above, portions of the signal 103 in
the second propagation mode may be extinguished as the signal 103
propagates through the mode combiner portion 108. The index matcher
112 may serve to control an amount of a signal transmitted by the
waveguide 100 that is in the second propagation mode.
The waveguide 100 includes an index matcher 112. The index matcher
112 is located proximate to the second end 116 and may be formed of
dielectric material. The index matcher 112 may support propagation
of the signal 103 in the second propagation mode. As described
above, portions of the signal 103 in the second propagation mode
may be extinguished as the signal 103 propagates through the mode
combiner portion 108. The index matcher 112 may serve to control an
amount of a signal transmitted by the waveguide 100 that is in the
second propagation mode.
FIG. 5 illustrates a simulation of surface currents in a circular
waveguide that does not include the dielectric material 110 and the
index matcher of FIGS. 1A and 1E. In FIG. 5, a signal enters the
waveguide 500 at a first end 514 and propagates along the entire
length of the waveguide in the TE11 mode. The surface current at a
second end 516 of the waveguide 500 includes longitudinal current
components at about zero (0) dBA/m.
FIG. 6 illustrates a simulation of surface currents in the
waveguide 100 of FIGS. 1A and 1E. In FIG. 6, a signal enters at the
first end 114 and propagates along the feed portion 104 in the TE11
mode. The signal propagates from the feed portion 104 to the
portion 106. As the signal enters and propagates along the portion
106 toward the second end 116, the dielectric material 110 of FIG.
1E causes portions of the signal to change propagation modes from
the TE11 mode to the TM11 mode, resulting in a mixed or multi-mode
signal (a signal having portions in both the TE11 mode and the TM11
mode). The signal propagates from the portion 106 to the mode
combiner portion 108. As described above, the mode combiner portion
108 has a length that causes energy propagating in the dominant
mode (TE11 mode) and the energy propagating in the second mode
(TM11 mode) to have a particular phase difference at the second end
116. The particular phase difference may result in cancellation of
longitudinal edge current at the second end 116. Thus, the surface
current at the second end 116 is lower (e.g., about -9 dBA/m) than
the surface current at the second end 516 of FIG. 5.
FIG. 7 illustrates a method 700 of propagating a signal through a
waveguide including dielectric material having a cross-sectional
area that varies along a length of a portion of the waveguide. The
method 700 of FIG. 7 may be performed by the waveguide 100 of FIGS.
1A and 1E.
The method 700 of FIG. 7 includes, at block 702, receiving a signal
at a waveguide that includes a waveguide wall and a dielectric
material having a cross-sectional area that varies along a length
of a portion of the waveguide. The signal may correspond to the
signal 103 of FIG. 1E. The waveguide may correspond to the
waveguide 100 of FIGS. 1A and 1E, the waveguide wall may correspond
to the waveguide wall 102 of FIGS. 1A, 1B, 1C, 1D, and 1E, and the
dielectric material may correspond to the dielectric material 110
of FIGS. 1C, 1E, 2, 3, and/or 4. The portion may correspond to the
portion 106 of FIGS. 1A and 1E. A shape of the waveguide wall is
associated with a dominant propagation mode as described above with
reference to FIG. 1A.
The method 700 of FIG. 7 includes, at block 704, converting a
portion of the signal from the dominant propagation mode to a
second propagation mode by propagating the signal through the
portion of the waveguide that includes the dielectric material. For
example, the waveguide may be a circular waveguide, and the portion
may convert portions of the signal from the TE11 mode to the TM11
mode as described above with reference to the waveguide 100 of FIG.
1A.
The method 700 of FIG. 7 further includes providing a particular
phase difference between portions of the signal propagating in the
dominant propagation mode and portions of the signal propagating in
the second propagation mode by, at block 706, propagating the
signal through a mode combiner portion of the waveguide. The mode
combiner portion may correspond to the mode combiner portion 108,
and the mode combiner portion may provide a particular phase
difference based on a length of the mode combiner portion as
described above. The particular phase difference may cause
cancellation of longitudinal edge currents as described above.
As described above, the cross-sectional area of an interior region
of the waveguide may be constant (or substantially constant). In
this implementation, the waveguide (e.g., the portion 106
(including the dielectric material 110)) emulates a perturbation in
the waveguide wall 102 to convert energy from a dominant
propagation mode to the secondary propagation mode without relying
on perturbations in the waveguide wall 102. Thus, the portion 106
converts propagation modes using an interior region 196 having the
same (or substantially the same) cross-sectional area as the
interior region 195 of the feed portion 104, thereby enabling
constant cross-sectional area waveguides to be retrofitted to
perform mode conversion by adding the dielectric material 110 to
the waveguides.
Referring to FIG. 8, a flowchart illustrative of a life cycle of a
platform, such as a vehicle (e.g., a land vehicle, an aerial
vehicle, or a water vessel) or a ground-based installation (e.g., a
building or a structure) including a waveguide that performs mode
conversion without waveguide wall perturbations is shown and
designated 800. During pre-production, the exemplary method 800
includes, at block 802, specification and design of a platform,
such as the aircraft 902 described with reference to FIG. 9. During
specification and design of the platform, the method 800 may
include, at block 820, specification and design of a signal
receiver or a signal transmitter having a waveguide. The signal
receiver or the signal transmitter may be part of a communication
system, such as the communication system 960 of FIG. 9, that may
employ an antenna, such as the antenna 903 of FIG. 9 (that includes
the waveguide), to transmit or receive a signal, such as the signal
103 of FIG. 1E. The waveguide may correspond to the waveguide 100
of FIGS. 1A and 1E. At block 804, the method 800 includes material
procurement. At block 830, the method 800 includes procuring
materials for the waveguide, such as the dielectric material 110 of
FIGS. 1C and 1E.
During production, the method 800 includes, at block 806, component
and subassembly manufacturing and, at block 808, system integration
of the platform. The method 800 may include, at block 840,
component and subassembly manufacturing (e.g., producing the
waveguide 100 or adding the dielectric material 110 and/or the
index matcher 112 to an existing constant cross-sectional area
waveguide) and, at block 850, system integration of the waveguide.
For example, the waveguide may be integrated into or used in
connection with an antenna, such as the antenna 903 of FIG. 9. At
block 810, the method 800 includes certification and delivery of
the platform and, at block 812, placing the platform in service.
Certification and delivery may include, at block 860, certifying
the waveguide. At block 870, the method 800 includes placing the
waveguide in service. While in service by a customer, the platform
may be scheduled for routine maintenance and service (which may
also include modification, reconfiguration, refurbishment, and so
on). At block 814, the method 800 includes performing maintenance
and service on the platform. At block 880, the method 800 includes
performing maintenance and service of the waveguide. For example,
maintenance and service of the waveguide may include replacing the
waveguide 100 or the dielectric material 110.
Each of the processes of the method 800 may be performed or carried
out by a system integrator, a third party, and/or an operator
(e.g., a customer). For the purposes of this description, a system
integrator may include without limitation any number of
manufacturers and major-system subcontractors; a third party may
include without limitation any number of venders, subcontractors,
and suppliers; and an operator may be an airline, a leasing
company, a military entity, a service organization, and so on.
Referring to FIG. 9, a block diagram of an illustrative embodiment
of an aircraft (e.g., an airplane or a drone) 902 that includes a
waveguide 100 configured to perform mode conversion is shown and
designated 900. As shown in FIG. 9, the aircraft 902 produced by
the method 800 may include an airframe 918, an interior 922, one or
more engines 944, an antenna 903, and a plurality of systems 920.
The systems 920 may include one or more of a propulsion system 924,
an electrical system 926, a hydraulic system 928, an environmental
system 930, a display system 950, and a communication system 960.
Any number of other systems may be included. The antenna 903
includes the waveguide 100 and additional antenna components 905,
such as a reflective dish. The antenna 903 may be part of the
communication system 960 and the one or more engines 944 may be
part of the propulsion system 924.
Apparatus and methods embodied herein may be employed during any
one or more of the stages of the method 800. For example,
components or subassemblies corresponding to the production process
808 may be fabricated or manufactured in a manner similar to
components or subassemblies produced while the aircraft 802 is in
service, for example at block 812. Also, one or more of apparatus
embodiments, method embodiments, or a combination thereof may be
utilized while the aircraft 902 is in service, at block 812 for
example and without limitation, to maintenance and service, at
block 814. For example, the waveguide 100 of FIGS. 1A and 1E may be
part of, or used in connection with, an antenna, such as the
antenna 903 of FIG. 9, which is used to transmit a signal, such as
the signal 103 of FIG. 1E while the aircraft 902 is in service.
The illustrations of the examples described herein are intended to
provide a general understanding of the structure of the various
embodiments. The illustrations are not intended to serve as a
complete description of all of the elements and features of
apparatus and systems that utilize the structures or methods
described herein. Many other embodiments may be apparent to those
of skill in the art upon reviewing the disclosure. Other
embodiments may be utilized and derived from the disclosure, such
that structural and logical substitutions and changes may be made
without departing from the scope of the disclosure. For example,
method steps may be performed in a different order than shown in
the figures or one or more method steps may be omitted.
Accordingly, the disclosure and the figures are to be regarded as
illustrative rather than restrictive.
Moreover, although specific examples have been illustrated and
described herein, it should be appreciated that any subsequent
arrangement designed to achieve the same or similar results may be
substituted for the specific embodiments shown. This disclosure is
intended to cover any and all subsequent adaptations or variations
of various embodiments. Combinations of the above embodiments, and
other embodiments not specifically described herein, will be
apparent to those of skill in the art upon reviewing the
description.
The Abstract of the Disclosure is submitted with the understanding
that it will not be used to interpret or limit the scope or meaning
of the claims. In addition, in the foregoing Detailed Description,
various features may be grouped together or described in a single
embodiment for the purpose of streamlining the disclosure. As the
following claims reflect, the claimed subject matter may be
directed to less than all of the features of any of the disclosed
examples.
Examples described above illustrate but do not limit the
disclosure. It should also be understood that numerous
modifications and variations are possible in accordance with the
principles of the present disclosure. Accordingly, the scope of the
disclosure is defined by the following claims and their
equivalents.
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